Chain saw



A. N. BLUM June 2o, 1944.

CHAIN SAW Filed Feb. 20, 1942 2 Shets-Sheet l A. N. BLUM June 2U, 1944.

CHAIN SAW 2 Sheets-Sheet 's Filed Feb. 2O 1942 Patented June 20, 1944 UNITED STATES PATENT OFFICE 13 Claims.

'I'his invention relates to chain saws, and more p particularly to portable chain saws wherein the tool is hand supported and air motors are utilized for actuating the cutting chain.

The invention contemplates a novel construction and assembly affording generally improved structural and functional characteristics in the saw, as hereinafter set forth.

More specific objects of the invention are to provide means for facilitating the holding and manipulation of the saw in conjunction with improved means for utilizing the exhaust from the aforesaid air motor for cooling and cleaning the running parts of the saw, as hereinafter fully described.

Another object of the invention is to direct a fluid blast from the exhaust of th'e air motor, or from a separate source, towards the sprocket, the chain and the guide rail in a direction approximately lengthwise of the cutting chain to effect thereby a saving of lubricating oil by impeding the centrifugal throw-off of lubricant from the rotating sprocket and chain, as well as a cleaning and cooling of the running parts.

The invention further resides in certain structural details hereinafter described and illustrated in the attached drawings, in which:

Figure 1 is a fragmentary longitudinal sectional view illustrating the head or driving end of a chain saw made in accordance with my invention;

Fig. 2 is a front elevational view of the same portion of the machine shown in Fig. 1;

Fig. 3 is an exploded view of the same portion of the machine showing certain of the details of construction;

Fig. 4 is a fragmentary View in perspective showing the details of the exhaust valve;

Fig. 5 is a view in perspective of one of the elements of the exhaust valve;

Fig. 6 is an exploded view in perspective illustrating a further detail of the air-cooling and cleaning system;

Fig. 7 is a section on the line 1'|, Fig. 2, and

Fig. 8 is an element of that portion of the machine shown in Figs. 6 and 7.

With reference to the drawings, I is the headstock of the chain saw within which is journaled the driven chain sprocket 2 and to which is secured one end of the chain guide `rail 3. 4 is the air motor housing to which is connected, by means in the present instance of a rigid xture 5, which also constitutes the actuating or live handle for the motor control valve, the flexible ductt which extends to the source of air pressure. The air motor as illustrated is a commercial article, and requires no description as to its mechanical parts and mode of operation. The shaft 1 of the motor is connected by suitable transmission elements, including in the present instance a coupling 8, a bevel pinion 9 and a bevel gear I0, with the driving sprocket 2, the said gears being mounted in the head-stock I, as shown.

In accordance with the present invention, I provide between the head-stock I and the motor housing 4, and uniting said housing to the headstock, a hollow casing member II, said member having at opposite sides thereof transversely projecting arms I2, I2 in which may be secured handle elements' I3, I 3. Preferably, and as shown in Fig. 1, 'these handle elements are detachably secured in the arms I2 and are adapted to be secured in the arms in either of the alternative g positions illustrated respectively in solid and broken lines in Fig. 1. One function of the casing member II, therefore, is to constitute a support for handle elements such as I3, I3. The rigid fixture 5 which attaches to the motor housing 4, as set forth above, is also adapted to form 9, handle for use in conjunction with one of the handles I3 in the support and manipulation of the saw.

It is to be noted that in the assembly shown in Fig. 1, the handles I3 are disposed at opposite sides of the vertical plane in which the toothed chain of the saw operates, this also being the plane oi' the sprocket 2, the cutting chain Il, and guide rail 3. For certain manipulations of the saw, it is desirable to have the handles disposed as shown in broken lines in Fig. 2, wherein the handles are disposed in a common plane which parallels the plane of operation of the toothed chain which in this figure is shown at I4. It may also be desirable to have the handles I3 disposed diflerently with-respect to the fixture 5 of the air motor. To these ends, the member II is attached to the head-stock I and to the motor housing 4 by means which permits concentric angular adjustment of the casing I I with respect both to the head-stock and the motor housing.

It is to be noted further that in the present instance the motor 4, member I I, head=stock vI, with sprocket 2, guide rail 3 and chain I4, are all arranged in line, and that all relative adjustments among these parts take place parallel with the shaft of the motor.

With reference particularly to Fig. 7, it is to be noted that the head-stock I comprises a` flange I5 which forms a seat for the casing II. The

iiange I5 is provided with a plurality of apertures I6 for reception of screws I1, said screws being threaded into tapped bosses I8 in the wall of the casing II. The flange I5 forms a seat for one end of the casing II, and since the apertures I6 and bosses I8 are uniformly spaced and symmetrically arranged, the casing II may be attached to the head-stock I in four different positions in the present instance. By means ofthis adjustment the handles I3 may be brought selectively into the relative positions illustrated in Figs. 1 and 2. V

With reference also to Fig. 3, it will be noted that the motor housing 4 is also provided with a ange I9, to which is secured, by-means of screws Y 2l, a ring 22. This ring forms a seat for the other end of the casing II, it being noted that, like the head-stock I, the ring has a transverse flange 23 which lits into the interior of the castapped for reception of screws (not shown) which secure the housing 4 to the casing. The apertures 24 and 25 are uniformly spaced and symmetrically arranged so as to permit the twof members to be secured together in a number of difierent positions of adjustment angularly about the axis of the shaft 1.

From the foregoing, it will be apparent that the arrangement aifords a high degree of exlbility of adjustment of the handle elements I3 and the fixture 5 with respect to each other and with respect also to the plane of operation of the toothed chain I'4. f

In accordance further with the present embodiment of my invention, the exhaust from the air motor is directed through a port 26 in line with the plane of the sprocket 2 and chain I4 into the interior of the casing II, the interior chamber being relatively of substantial volume, and the wall of the casing is provided with a port 21 for by-passing the air to the atmosphere. The e'ective size of the port 21 is regulated by means of a valve plate 28 which is slidably supported in the interior of the casing Il, as illustrated in Fig. 4. The plate 26 may be adjusted by means of a series of apertures 29 in the plate, at least one of which is continually exposed in the oiset portion 3i of the port 21 and into which the tip end of a file or other suitable tool or instrument may be inserted for applying the necessary pressure to shift the plate. The plate is resilient and is normally flat, see Fig. 5, and is held in i'lexure in the casing between the `vflanges 33, 30 of the latter. This exure creates frictional resistance which tends to retain the plate in adjusted position.

The wall of the head-stock I is provided with an elongated port 32 through which connection is established between the interior of the casing il and the sprocket space of the head-stock I. As shown in Fig. 1, the port 32 is arranged in alignment with the plane of the driving sprocket 2 and the chain it which operates on this sprocket, and in line also with the opening 33 in the head-stock l through which the chain passes and in which also the proximate end of the guide rail 3 is secured,` Air passing from the interior of the housing II through the port 32 is thus projected upon and approximately lengthwise of the toothed chain and its sprocket 2 and also on the adjoining end of the guide rail 3, into the slots 33 of this rail, in which slots thechain is guided, and also into the kerf. The volume of lated by means of the valve plate 2B which controls the by-pass port 21 in the wall of the casing II. Means is also provided for varying the slotted port 32 so as to regulate the velocity of air as it passes through this port to the sprocket space of the head-stock, as well as the point or points at which the discharge of the air into the sprocket space takes place. This regulating means comprises in the present instance an elongated valve plate 35 which is slidably secured in the wall of the head-stock I, as shown in Fig. 6. The cover-plate 36 of the head-stock I is provided with a solid boss 31, which in assembly engages or lies in'proximity to the wall of the head-stock body immediately above the slotted port 32, see Fig. 2. 'As shown in Fig. 6, the outer face of the boss 31 is slotted at 3B for reception of the valve element 35. When the plate is in position, the edge 42 of the head-stock, the screw I1 and the spring washer 4I function to retain and guide the said valve element. By adjusting the plate 35 upwardly or downwardly, the effective opening of the slot 32 may be varied as required, as

' Well as the area of the impingement of the airthe air directed through the port 32 may be regu- 75 stream against the sprocket and along the chain. It will be noted that in any position of the motor with relation t`o the guide rail and chain, the air blast will always be towards the sprocket and along the chain, the guide rail and the kerf. By reason of this structurally established direction of the air blast along the kerf, the cleaning and cooling action of the exhaust airstream will still be substantially available even if the coverl plate 36 is removed, as might on occasion be necessary under certain operating conditions.

It will be noted, as shown in Fig. 8, that the valve plate 35 has at its lower` end an outtumed flange 39 which in assembly enters the port 32 and acts as a stop to prevent complete withdrawal of the valve plate 35 from the headstock. Means is also provided for tensioning the plate 35 so that it will remain in any adjusted position. This device, shown in Fig. 7, consists Iof a spring washer 4I underlying the head of the retaining screw I1, which screw passes through the aperture I6 of the flange I5 which immediately adjoins the plate 35. The washer 4I bears resiliently against the face of the plate 35, see Fig. '1, and thereby retains the plate in any adjusted position without, however, interfering with the adjustment operation.

The member or casing II functions, therefore, as a medium for equalizing, controlling and regulating the application of the exhaust air from the motor ii to the working elements of the chain saw for cooling and cleaning the latter. The relatively large interior space within the casing l I acts as an accumulating and equalizing chamber, within which by means of the valve 2t the air pressure built up by the exhaust may be regulated, and the amount of velocity of the air exhaust drawn from this pressure chamber for use in cooling and cleaning the saw may be accurately regulated and directed by the valve 35 without substantially reducing the eiciency of the air motor.

The direction of the air blast against the groove ofthe sprocket 2 has the further effect of conserving the oil carried by the chainand throwna minimum oil consumption. In this same respect chain saws operated by other than air motors may be provided with a separate duid stream, or by a blower driven by the chain saw motor and connected with port 32, whereby the fluid blast is again directed andl regulated so that it blows towards the groove of the sprocket and` approximately lengthwise of the chain and rail, no matter in what position the latter might be withfrespect to the motor.

I claim:

1. In a chain saw having a head-stock anda chain-supporting element mounted in said stock,

an air motor unit, a casing unit interposed between and connecting the motor unit with the head-stock, transmission mechanism, extending through the casing and operatively connecting the motor with the chain-supporting element, means for. directing the exhaust air from the motor into the casing, a port in the head-stock directed toward the chain-supporting element, a port in said casing opening to the atmosphere, and valve means for regulating the effective area of each of saidports.

2. In a chain saw, a head-stock having adjoining chambers, a chain-supporting element in one of said chambers, transmission mechanism operatively connected with said element and mounted in the other of said chambers, an opening in the first-named chamber and a toothedv chain extending through said opening and around said supporting element, a second opening at the opposite side of said chamber and in alignment with the first-named opening, an air motor unit, a casing unit interposed between and connecting the motor unit with the headstock, transmission means extending through said casing and operatively connecting the motor with the transmission elements in said second head-stock chamber, and means for directing the exhaust air from the motor into the casing for passage through the second-named opening into the head-stock.

3. In a chain saw, an air motor, a head stock, a chain-supporting element rotatably mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element, and means in said head stock for directing the exhaust of said motor against said element and the portion of the chain in curviiorm engagement therewith, .and substantially in the plane of said element.

4. In a chain saw, an air motor, a head stock, a cham-supporting element rotatably mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element, and means in said head stock for directing the exhaust of said motor against said element and the portion of the chain in curviform engagement therewith, and substantially in the plane of said element, said directing means comprising an aperture in said head stock in fixed predetermined relation to vsaid element.

5. In a chain saw, a motor, a head stock, a chain-supporting element rotatably mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element, means providing an intermediate chamber of substantial volume interposed between said motor and said head stock, means for accumulating a uid in said chamber, a pair of ports in the wal1 of said chamber, one of said ports being arranged to direct a blast of said fluid from the chamber against said element and chain and substantially lengthwise of the latter and the motor and said head stock, me'ans for directingV the exhaust from said motor into said chamber, a pair of ports in the wall ot said chamber, one of said ports being arranged to direct said exhaust air from the chamber against said element and chain and substantially lengthwise of the latter, and the other port constituting a by-pass for a portion of said exhaust air to the atmosphere, and valve means to regulate at least one of said ports.

7. In a chain saw, an air motor, a head stock, a chain supporting element rotatably mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element, an intermediate member interposed between said motor and said head stock and having therein a chamber arranged to receive the exhaust from said motor, means in said-head stock to direct the said exhaust from said chamber against said element and chain and substantially lengthwise of the latter, said intermediate member being relatively adjustable with respect to said head stock, and carrying handle means adjustable with said member.

8. In a portable hand-held chain saw comprising a head stock structurally permanently related to the cutting plane of the saw, a motor unit and an intermediate member connecting the said unit with the head stock; said unit, head stock and intermediate member being arranged in line substantially parallel to said cutting plane, and said member being rotatably adjustable about said line with respect to the head stock: and to the motor unit, handle means carried by the intermediate member and extending approximately parallel to said line, and means for adjusting said handle means on the said member longitudinally of said line, the plane in which said handles are held being angularly adjustable with said intermediate member relative tothe said cutting plane of the saw.

9. In a portable hand-held chain saw comprising a head stock structurally permanently related to the cutting plane of the saw, a motor unit and an intermediate member connecting the said unit with the head stock, said unit, head stock and intermediate member being arranged in line substantially parallel to said cutting plane, a handle on said member extending approximately parallel to said line, and a handle element on saidunit extending substantially at right angles to said line and aording with said first-named handle a means for supporting and manipulating the saw by hand, said member and unit being angularly adjustable about said line with respect to the head stock so as to correspondingly angularly adjust the handles jointly with respect to the said cutting plane of the saw.

10. In a portable hand-held chain saw comprising a head stock structurally permanently related to the cutting plane of the saw, a chainsupporting element rotatably mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element, an air motor unit, and an intermediate hollow member connecting the said unit with the head stock. said unit, head stock and intermediate member being arranged in line substantially parallel to said cutting plane, means for exhaustingv air from said motor into the interior of said member, means in said head stock for directing the exhaust air from the member into the head stock and against said element and chain and substantially lengthwise of the latter, and handle means carried by said intermediate member, said member being angularly adjustable about said line with respect to the head stock so as to correspondingly adjust the plane of said. handle means with respect to the said cutting plane of the saw.

11. In a portable hand-held chain saw comprising a head stock structurally permanently elated to the cutting plane of the saw, a chainupporting element rotatably mounted ln the head stock, 'a chain engaged with and operating 2@ with the interior of the head stock, means for a@ esame@ directing the exhaust air from said chamber against said element and chain and substantially lengthwise of the latter, handle means on said member and on said motor unit, and means providing for angular adjustment oil the intermediate member about said line with respect both to the motor unit and to the head stock.

12. In a power chain saw, a head stock, a chain supporting element mounted in the head stock, a chain engaged with and operating in the plane of rotation of said element and extending in a substantially straight run from the latter, a guide rail for guiding the said substantially straight portion of the chain extending from said element, said guide rail being attached to said head stock and being arranged to transmit working pressure to the chain in the direction of said plane in order to produce a kerf in the work piece, means providing a uid stream and means for directing said stream toward said element and the portion of the chain in curviform engagement with said element and approximately toward said kerf lengthwise of the said straight portion of the chain and of the guide rail.

13. A power chain saw in accordance with claim 12 wherein the means for directing the iiuld stream includes an aperture in the head stock in xed predetermined relation to said element.

ARTHUR N. BLUM. 

